Generic update

I also completely broke physics while doing cleanup on the interface, oops... everything except joints seems to be working now, though I do have to do some more implementation-level cleanup. After the physics interface is nailed down, I'm more or less ready to go to documentation/testing/bug fixing mode for Spineless 0.3. Hoorays!

...not much else happening. I'll post more about Secret Game Project after I have implemented collision detection for triangle meshes (and by extension, heightmaps). As I said, I'll let SGP pretty much drive the development of Spineless now (but of course keeping engine code generic as usual).

Any wishes about which part of Spineless I should discuss next? Resource management perhaps?